This invention relates to a shaft cooler for dry quenching of coke and other fuel pieces, and more particularly, to such a cooler having a vertical refractory chamber with a top conical portion formed with a central charging opening and a substantially cylindrical portion disposed below the top conical portion and having a bottom discharge opening; the interior of the cylindrical portion communicating with a number of flue-gas passages at the bottom part of a ring main which extends around the top part of the cylindrical portion.
In West German patent publication No. 1,471,598, there is disclosed a shaft cooler in which masonry material extends continuously over the entire height of the chamber. In practice, it has been found that the masonry zone in this construction below the flue-gas passages is particularly at risk and, therefore, must be regarded as a weak zone. The main risk is due to the high specific pressure loads because of the weight of the inner masonry disposed above the passages for the flue gas. Collapse of the masonry during operation of the shaft cooler is frequent in these zones which causes unwanted disturbances and downtimes. To reduce the bearing pressure on the support walls near the flue-gas passages, it has been suggested to reduce the weight of the masonry in the conical part of the shaft cooler. Efforts have also been made to divert more of the weight of the bricks in the conical portion to the outer masonry located outside the flue-gas main. However, no satisfactory improvement has yet emerged.